激光焊接1Cr17铁素体不锈钢温度场数值模拟

采用SYSWELD有限元软件,建立了激光焊接铁素体不锈钢的3D有限元模型.考虑材料的热物性参数与温度的非线性关系以及表面对流和辐射热交换的影响,分析了激光焊接过程中温度场的分布及焊缝表面不同点的热循环变化,并进行了实验验证.结果 表明:焊接一段时间后,焊接温度场呈现准稳定状态,随焊接热源的继续移动,焊缝区各点的温度基本保持稳定.沿着焊接方向,焊缝表面不同节点Tmax-T800和T800-T300冷却速度逐渐降低.另外,焊缝熔池的模拟结果和相同工艺参数的实验结果相吻合,证明了焊接过程中数学模型建立的合理性,模拟结果为铁素体不锈钢焊接过程的优化提供了理论依据.     

T型长板焊接温度场与应力场分析

利用有限元软件Ansys对4 m长T型焊接节点焊接过程进行数值模拟。采用间接耦合的方式,先进行热分析得到温度场,然后进行结构应力分析,最终得到应力场。研究发现,焊接之后会产生极不均匀的温度场,进而会产生较大的焊接残余应力以及残余变形,将计算结果与试验结果进行对比,温度场符合度较高,焊接残余变形有一定误差。为了研究焊接边界条件对于焊接残余变形的影响,对其进行参数分析,发现焊接时将板支撑焊接可以有效地减少残余变形。     

铝合金激光深熔焊接热过程有限元数值模拟

对铝合金5A06简体纵缝进行激光深熔焊接。建立了该条件下的焊接热源模型,热源模型由沿激光入射方向的旋转高斯体热源构成。使用该热源模型和ANSYS有限元分析软件对前述的试验进行了数值模拟。为制定和优化焊接工艺提供必要的参考。     

不同热过程对激光焊热影响区性能的影响

在Ｇｌｅｅｂｌｅ－２０００热力动态模拟系统上采用自行设计的高速可控激冷装置对ＵＬＣＢ６００钢激光焊接热影响区在焊前预热、不预热及 后激光回火三种状态下的热过程进行了模拟,并对相应的组织性能进行了研究。研究结果表明,模拟热影响区在上述三种状态下的冲击韧性均远高于基材,且经焊前预热或激光回炎后激光焊热影响区最高硬度值下降。     

惯性摩擦焊过程温度场及变形场的数值模拟

惯性摩擦焊接是一种广泛应用的高效、可靠、节能及环保的固态焊接方法.该方法在航天航空领域已广泛应用.本文分析了惯性摩擦焊接过程高度非线性的特点,在此基础上建立了一个基于二维轴对称的惯性摩擦焊接过程有限元热力耦合计算模型.计算区域划分成四节点等参单元,热物性参数和力学性能参数随温度变化,同时考虑了焊接热流随时间的变化、表面对流和辐射换热以及飞边的影响.利用有限元分析软件MSC Marc对同质材料GH4169-GH4169惯性摩擦焊接接头区的瞬态温度场及应力-应变场的分布进行了计算分析.使用热电偶点对焊接接头部分若干点的温度进行了实时测量.结果表明温度场的计算结果与实测值符合较好.另外,还讨论了工艺参数对摩擦焊接接头区应力分布以及飞边形状的影响.     

金属板焊接件残余应力数值模拟的分析及应用

文章以ANSYS有限元数值分析软件为基础,给出了焊接模拟的分析流程,以2024-T4铝合金为例,耦合方式采用了直接的热-结构耦合,焊接热源选用生死单元法进行加载,焊接热源的移动运用ANSYS参数化语言实现,另外分析了比热容对焊接残余应力的影响。     

Q960超高强钢多道焊接头残余应力的数值研究

以Q960超高强钢为研究对象,基于有限元软件,建立热—冶金—力学有限元模型,模拟焊接温度场和残余应力分布.计算结果与接头截面熔池形貌和盲孔法测量的表面应力结果吻合良好,验证了有限元模型的准确性.基于验证模型,讨论和分析了考虑固态相变对Q960超高强钢多道重熔过程中表面及内部应力的分布特征.结果表明:考虑固态相变时,Q960超高强钢单道焊后,焊接接头以拉伸残余应力为主,峰值应力位于热影响区.同时,固态相变效应能够显著降低焊缝中残余应力的大小,以及显著影响横向残余应力的分布.此外,随着焊道数的增加,焊缝中心的横向残余应力呈"阶梯"趋势上升,且在热影响区位置出现局部压应力峰值.     

1800 MPa热成形钢与CR340LA低合金高强钢激光焊接性能

采用光纤激光焊接设备对1800 MPa级热成形钢与CR340LA低合金高强钢进行对接激光拼焊,研究了不同激光焊接功率和焊接速度下焊接接头的组织演变规律及热冲压成形性能,并对焊接接头的力学性能和硬度进行了分析。结果表明,3种焊接工艺下激光拼焊原板综合力学性能相差较小,由焊接接头造成的伸长率和抗拉强度的损失均在母材的28.3%和9.1%以内。激光焊接后焊缝区均为粗大、高硬度的马氏体结构;两侧热影响区组织主要为铁素体和马氏体,接头未出现明显的软化区。激光拼焊原板拉伸试样均断裂于CR340LA母材区,距离焊缝12 mm左右,且存在焊缝隆起现象。选取焊接功率和焊接速率分别为4000 W和0.18 m·s?1的焊接试样在高温下进行热冲压成形检测,未出现焊缝开裂,热成形后拼焊板具有良好性能,满足汽车激光拼焊板使用要求,拉伸结果表明,试样断裂位置与未热冲压成形前一致,均位于CR340LA母材区,拉伸过程中,焊缝向高强度母材侧偏移,在弱强度母材侧产生应力集中并缩颈断裂。      

轧辊温度场及轴向热凸度有限元计算

采用大型有限元分析软件 ANSYS对四辊轧机工作辊的温度场进行了模拟 ,在模拟过程中 ,考虑了轧辊和轧件间的瞬态热接触和对流边界 ,动态分析了热轧时工作辊的升温过程 ,预测了工作辊的瞬态温度分布 ,并将所得的温度分布用于热凸度的近似计算中 ,其计算结果与文献结果相吻合     

特大型挖掘机铲斗体焊接温度场分析

根据焊接的实际工艺建立了多层多道焊的有限元数值分析模型,对特大型挖掘机铲斗体关键的焊缝处使用过渡性网格进行划分。利用ABAQUS有限元软件对铲斗体焊接温度场进行了模拟仿真,得到其焊接过程的温度场的分布规律及热循环动态变化过程。     

预热对铍环激光束钎焊过程的影响研究

研究预热对铍环激光束钎焊过程温度场和应力场分布的影响。采用轴对称模型和热力解耦的有限元方法，并假定沉积到钎缝表面的激光束能量为Gauss分布，预热通过在焊接加热前添加一个能量密度低、有效加热半径大的单独工况实现。结果表明，预热使镀环钎缝外表面焊接最高温度增加，温度梯度减小，但焊深明显增加；采用预热工况焊接后，钎缝附近塑性变形区焊接残余应力明显减小，而热影响区残余应力增大。从整体分布来看，预热使铍环外表面焊接残余应力分布均匀化。对铍环外表面钎缝附近焊接残余应力进行X射线应力测试，并与有限元分析结果对比，二者应力变化趋势基本一致。     

Finite Element Simulation of Laser Welding of 904L Super Austenitic Stainless Steel

Experiments on Laser butt welding of 904L super austenitic stainless steel was conducted using diffusion cooled 3.5 kW slab CO₂ laser welding system. The weld geometries such as bead width and depth of penetration were measured. The laser welding process has also been simulated using ANSYS a Finite Element Analysis tool. The effect of laser power, welding speed and focal point position on the bead geometry was investigated. The experimental plan was developed based on the Taguchi technique. The comparison of the results of the simulation indicates that Finite Element Method (FEM) can predict the responses adequately within the limits of welding parameters being used. It is suggested that FEM can be used as a tool for predicting the bead geometry at low values of heat input on laser welding.     

A study on heat source equations for the prediction of weld shape and thermal deformation in laser microwelding

In the area of laser welding, numerous studies have been performed in the past decades using either analytical or numerical approaches, or both combined. However, most of the previous studies were process oriented and modeled conduction and keyhold welding differently. In this research, various heat source equations that have been proposed in previous studies were calculated and compared with a new model. This is to address the problem of predicting, by numerical means, the thermomechanical behavior of laser spot welding for thin stainless steel plates. A finite-element model (FEM) code, ABAQUS, is used for the heat transfer and mechanical analysis with a three-dimensional plane assumption. Experimental studies of laser spot welding and measurement of thermal deformation have also been conducted to validate the numerical models presented. The results suggest that temperature profiels and weld deformation vary according to the heat source equation of the laser beam. For this reason, it is essential to incorporate an accurate model of the heat source.     

Prediction of laser-spot-weld shape by numerical analysis and neural network

The finite element method (FEM) and neural network were applied for predicting the bead shape in laser spot welding of type 304 thin stainless steel sheets. The parameters of pulsed Nd:YAG laser spot welding such as pulse energy, pulse duration, sheet metal thickness, and gap between sheets were varied for various experiments and numerical simulations. The penetration depth and nugget size of spot welds measured for specimens without gap were compared with the calculated results to verify the proposed finite element model. Sheet metal thickness, gap size, and bead shape of the workpiece without gap were selected as the input variables for the back-propagation learning algorithm of the neural network, while the bead shape of the workpiece with and without gap was considered as its output variable. Various combinations of stainless steel sheet metal thickness were considered to calculate the laser-spot-weld bead shape of the workpiece without gap, which was then used as the input variable of neural network to predict the bead shape for various gap sizes. This combined model of finite element analysis and neural network could be effectively applied for the prediction of bead shapes of laser spot welds, because the numerical analysis of laser spot welding for the workpiece with gap between two sheets is highly limited.     

型钢轧辊激光相变硬化策略的设计与实施

为了实现激光相变硬化工艺参数的优化选择,基于有限元仿真技术,研究了激光扫描过程中的温度场分布规律,并结合材料相变曲线,预测了轧辊淬硬层的宏观形态。进而,根据宏观表面硬度和显微组织的实验结果,确定了适于半钢材质激光强化的参数组合。经磨料磨损实验表明,半钢材质的型钢轧辊经激光强化后,其耐磨性显著提高。     

umerical Study on Welding Line Behavior of Deep Drawing TWB Process

 The FEM technology is used to analyze the welding line movement behavior of deep drawing TWB sheet with different thickness. It is found that high stress fields are concentrated around the welding line and large residual stresses are left. The effect of the welding line movement is like a rigid string and the selected nodes of the thin part near the welding line show the related larger strain.     

Numerical Study on Welding Line Behavior of Deep Drawing TWB Process

Tailor-welded blanks ( TWB) are composed oftwo or more sheets of metal with dissi milar strengthand/or thickness that are weldedinto a single blank.TWBs are stampedinto automotive body panels andoffer reduced part weight and i mproved materialuse[1]. They are most commonly fabricated using alaser welding process , which creates a narrow weldand a heat-affected zone ( HAZ) at the junction ofdissi milar sheets . As the variety of TWB applications increases ,the effects of the weld on blank f…     

激光焊接技术研究

介绍了激光焊接技术的研究概况,包括焊接用激光发生器、激光焊接工艺参数、激光焊接工艺特点等,重点介绍了激光焊接在汽车工业中的应用情况.     

Laser Welding of Ultra-Fine Grained Steel SS400

Steeliswidelyusedbecauseofitsgoodcompre hensive properties ,plentyofresourceandlowerprice .Thestrengthandtoughnessaretwoimpor tantpropertiesofsteels ,andpeoplemakeeffortstoincreasetheirvalues .Addingalloyingelementandcontrollingmicrostructurearetwobasicwaystoac complishtheaim .Therefinedmicrostructureob tainedbyprocessingtechniqueenablesthestrengthandtoughnessofsteeltobeincreasedwithoutaddingalloyingelementandtheratioofperformance costtobeincreased .Theultra finegrainedsteelshavefer ritegrains…